The Galois Complexity of Graph Drawing: Why Numerical Solutions are Ubiquitous for Force-Directed, Spectral, and Circle Packing Drawings

Many well-known graph drawing techniques, including force directed drawings, spectral graph layouts, multidimensional scaling, and circle packings, have algebraic formulations. However, practical methods for producing such drawings ubiquitously use iterative numerical approximations rather than constructing and then solving algebraic expressions representing their exact solutions. To explain this phenomenon, we use Galois theory to show that many variants of these problems have solutions that cannot be expressed by nested radicals or nested roots of low-degree polynomials. Hence, such solutions cannot be computed exactly even in extended computational models that include such operations.Comment: Graph Drawing 201

Whistleblowing e direito penal : an?lise de uma pol?tica criminal de combate aos crimes econ?micos fundada em agentes denunciantes

Submitted by PPG Ci?ncias Criminais ([email protected]) on 2018-05-09T18:45:14Z No. of bitstreams: 1 Ca?ssio - Dissertac?a?o completa.pdf: 7347040 bytes, checksum: 9fcfee32ac1d6666851aa8feef19f2aa (MD5)Approved for entry into archive by Caroline Xavier ([email protected]) on 2018-05-15T12:26:06Z (GMT) No. of bitstreams: 1 Ca?ssio - Dissertac?a?o completa.pdf: 7347040 bytes, checksum: 9fcfee32ac1d6666851aa8feef19f2aa (MD5)Made available in DSpace on 2018-05-15T12:32:08Z (GMT). No. of bitstreams: 1 Ca?ssio - Dissertac?a?o completa.pdf: 7347040 bytes, checksum: 9fcfee32ac1d6666851aa8feef19f2aa (MD5) Previous issue date: 2018-03-20This thesis is mainly based on the intersection between whistleblowers, disclosure of sensitive information and criminal law. For that matter, the research aims to examine the juridical conception of whistleblowing and is set to understand why whistleblowers around the world are worthy of encouragement and legislative protection at the same time that a lot of them are criminally prosecuted. The fact is that their disclosure of information leads law enforcement authorities to discover illicit acts (of which the whistleblower has knowledge but is not involved). Thus, nowadays several countries around the globe created laws to incentive (legal protection against reprisals) and reward whistleblowers (with a percentage of the monetary sanctions collected by the state if the information delivered by the whistleblower was valuable to a successful legal judicial or administrative action). Unlikely others institutes related to criminal prevention such as plea-bargaining or criminal compliance, the practice of whistleblowing have its own specifications that will be examined in this study. The importance of whistleblowing has resulted in its legislative expansion due to the possibilities of discovering and preventing illegal practices through the disclosure of information by a whistleblower. The focus of my research lies in this figure that arouses so much interest, sometimes seen as heroic or as a traitor. Therefore, the research develops reflecting the possibilities of constructing a criminal policy based on this innovative kind of law.O presente estudo objetiva examinar o instituto do whistleblowing, desde a sua conceitua??o jur?dico-penal, passando por sua constru??o social enquanto fen?meno, at? sua expans?o internacional enquanto objeto de cria??o legislativa. A figura do whistleblower, um sujeito denunciante, al?m de recente, traz consigo complexidades que a tornam digna de tutela. Tratase de uma figura que, na condi??o de membro (ou ex-membro) de determinada empresa ou organiza??o (seja p?blica ou privada), leva ?s autoridades o conhecimento que det?m sobre atividades il?citas, pr?ticas anti?ticas e toda a sorte de crimes que estavam sendo praticados sob controle dos pr?prios membros de tal organiza??o. Diferentemente de outros institutos, em mat?ria penal, que v?m ? mente quando se menciona den?ncia e dela??o ou, ainda, quando se pensa no aspecto de ado??o de mecanismos preventivos a fim de evitar delitos dentro de institui??es, a pr?tica de whistleblowing consiste em instituto com conceitua??o espec?fica. O atual entendimento, em diversas legisla??es do mundo, ? que a figura do whistleblower ? digna de tutela e, tamb?m, de incentivo, pois demonstrou ser instrumento valioso tanto na preven??o, quanto no descobrimento de condutas delitivas

On Simultaneous Planar Graph Embeddings

We consider the problem of simultaneous embedding of planar graphs. There are two variant

On the query complexity of testing orientations for being Eulerian

We consider testing directed graphs for being Eulerian in the orientation model introduced in [15]. Despite the local nature of the property of being Eulerian, it turns out to be significantly harder for testing than other properties studied in the orientation model. We show a non-constant lower bound on the query complexity of 2-sided tests and a linear lower bound on the query complexity of 1-sided tests for this property. On the positive side, we give several 1-sided and 2-sided tests, including a sub-linear query complexity 2-sided test for general graphs. For special classes of graphs, including bounded-degree graphs and expander graphs, we provide improved results. In particular, we give a 2-sided test with constant query complexity for dense graphs, as well as for expander graphs with a constant expansion parameter